The White Castle Experiment

If you haven't yet seen Super Size Me, it's worth renting. In it, filmmaker Morgan Spurlock makes himself the subject of an experiment to find out what will happen to his body if he only eats McDonald's fast food for 30 days. Predictably, his health deteriorates, his cholesterol skyrockets, he grows lethargic, and his waistline expands dramatically.

However, the idea of conducting a fast-food diet experiment wasn't original to Spurlock. That honor goes to Jesse McClendon, a researcher at the University of Minnesota, who in 1930 fed a volunteer a diet of only White Castle hamburgers for 13 weeks. From the U of M Medical Bulletin:

McClendon knew that earlier studies had shown that adult dogs fed for a month on only lean meat appeared to fare well, and that humans on temporary all-meat diets lost calcium and phosphorus but didn't develop deficiency diseases. He planned to feed a single experimental subject only White Castle hamburgers—including the bun, onions, and pickles—and water for 13 weeks.
A willing subject presented himself: Bernard Flesche, a U of M medical student working his way through school. Flesche kept a diary during the ordeal. "He started out very enthusiastic about eating 10 burgers at a sitting," notes his daughter, Deirdre Flesche, "but a couple of weeks into it, he was losing his enthusiasm." His sister frequently tried to tempt him with fresh vegetables, but Flesche allowed nothing but White Castle Slyders™ to pass his lips.

Flesche survived his ordeal without developing any significant health problems. The owner of White Castle interpreted this to mean that a hamburger diet is healthy and heavily promoted the experiment in advertisements. Flesche, however, who had once been a hamburger lover, developed a permanent aversion to them. He never willingly ate a hamburger again.